Patent GB-1403561-A (GB)
Title: Dual temperature exchange systems
IPC: B01D59/33
Filed: 1972-03-22
Abstract: 1403561 Exchange process DEUTERIUM CORP 22 March 1972 [22 March 1971] 13477/72  Heading C1A A fluid containing a concentrate of a first material by exchange at two different temperatures said first material with a second material between chemically different physically separable first and second fluid phases in which (a) said second fluid phase is passed through each of the second and first units in that order of a pair of exchange units, (b) flows of said first fluid phase are passed in counter-current with said second fluid phase in first and second units of said pair, (c) the first and second units are maintained at different temperatures to cause said second fluid phase to become enriched in said first material in passing through said second unit and to become impoverished in said first material in passing through said first unit, and to cause the first fluid phase to become enriched in said first material in passing through said first unit and to become impoverished in said first material in passing through said second unit, and in which at least a part of one of the enriched fluids is withdrawn, (d) a first flow of said fluid phase containing said materials being delivered from a source thereof and passed in countercurrent exchange with said impoverished second fluid in a first deliveryto-discharge path through a portion only of said second unit close to the end at which said fluids are most impoverished in said first material and (e) a second flow of first fluid phase is passed in a second delivery-to-discharge path exclusive of said first path in countercurrent exchange with said second fluid phase in other portions of said first unit and said second unit of said pair of units and as an enriched flow between said units. The first and second fluid phases may be liquid water and gaseous hydrogen sulphide, the first material being deuterium. The first flow of the first fluid phase may be saline water (e.g. sea water) and the second flow thereof may be water relatively free of saline content. In the known process (steps a, b, and c) shown in Fig. 1, a feed supply fluid (e.g. water) is delivered at a-1 to tower T1 which is kept at a given temperature (e.g. cold) to cause enrichment of the feed supply fluid and impoverishment of the auxiliary fluid AF-1 (e.g. H 2 S) in a desired material (e.g. deuterium). The feed supply fluid passes via b-1 to an inter tower processing system c-1 from which a product P is withdrawn, the main feed supply flow passing via d-1 into a second tower T2 also at a given but different temperature (e.g. hot). This results in impoverishment of the feed supply fluid and enrichment of the auxiliary fluid which is discharged at e-1. The solid line path indicates water flow and the broken line path gaseous H 2 S flow. Fig. 2, shows an embodiment of the invention, in which the feed to disposal path F-D is confined to the lower portion of tower T2 instead of both towers as in Fig. 1. The feed enters at a2 below a partition sS extending across the tower but permitting passage only of the auxiliary fluid AF2. The other fluid exchanges with the auxiliary fluid AF2 in the upper section of tower T2, being withdrawn from above the partition s2 for recirculation through T1 via conduit m2. Additional feed may be added by means of valve j2 into the recirculating fluid in m2, an equivalent amount being withdrawn from circulation via conduit with valve k2. The withdrawn quantity may be combined with primary feed supplied at a2 and pass through the lower part of tower T2 and be discharged at e2, thus improving the efficiency of the lower portion of T2 by making a larger quantity of the desired material (e.g. dueterium) available for exchange with the auxiliary fluid phase. Other modifications are described in the Specification.